Need Feedback: FWs that play nice w/XPx64

I am currently running CIS v3.14 (no AV) with Avast 5. I've been thinking about moving from CIS as I really don't like where they're headed with v4.

I would prefer to stick with freeware. My choices appear to be Outpost or Private Firewall as PC Tools does not appear to compatible with XPx64. Maybe I should wait for the 64 bit version of Online Armor.

My only real concern here is that my choice plays nicely with XPx64 (reasonable overhead, no slowdowns or driver conflicts...)

If anyone here has direct experience with any of the above and XPx64, I would certainly appreciate your input.

Despite working reasonably well, I'm looking to move away from Comodo. Version 3.14 will not likely be supported much longer given the release of version 4. From what I've seen and read, I won't be upgrading to v4 anytime soon, if ever.

FYI: The unorthodox manner by which Avast 5 updates causes Comodo 3.14 to write new registry entries each time it updates. I have deleted over 1500 entries since Avast 5 was released. If you have a good registry utility, search for avast.setup and SF.bin. I go in and prune out those that are safe to delete every 2 or 3 days. It's just another reason why I'd like to switch firewalls.